量器不确定度在实验室标准溶液配制过程中的评定

Evaluation of uncertainty of measuring instruments in preparing standard solution

中文关键词:  移液管  移液枪  容量瓶  不确定度  标准溶液配制

英文关键词:pipettes  pipetting guns  volumetric flask  uncertainty  standard solution preparation

中文摘要:

      目的 评价移液管、移液枪与容量瓶配制标准溶液的不确定度。方法 评定并比较量器3个不确定度分量(测量重复性、校准与温度效应), 评定并比较不同标准溶液配制方案量器引入的不确定度。结果 测量重复性、校准与温度效应3个不确定度分量对量器不确定度贡献率不相上下; 量程2~100 mL容量瓶, urel容量瓶为0.398%~0.515%; 移液枪与移液管移取0.500~1.000 mL乙腈, urel移液管(0.587%~1.010%)高于urel移液枪(0.580%~0.595%), 主要是urel重复性引起的; 移液枪移取0.100~0.500 mL乙腈, urel移液枪为0.595%~0.917%; 移液枪移取20~100 μL乙腈, urel移液枪为0.917%~1.755%; 3种标准工作曲线配制方案, urel量器依次为1.768%、2.204%和2.328%。结论 移液管对实验人员的操作要求更高, 移液枪更易操作; 测量重复性实验实现了量器定期标定或校准; 移取不同体积液体时, 移液管与移液枪有不同的优先选择; 定容时优先选用小量程容量瓶; 标准储备液与标准中间液选用移液管与容量瓶配制, 标准工作曲线可完全用移液枪配制。

英文摘要:

      Objective To evaluate the uncertainty of standard solution prepared by pipette, pipette gun and volumetric flask. Methods Evaluated and compared the three uncertainty components which were repeatability, calibration and temperature effects, and evaluated and compared the uncertainty introduced by measuring instruments of different preparation plans for standard solution. Results The three uncertainty components of measurement repeatability, calibration and temperature effect had almost the same contribution rate to the uncertainty of measuring instruments. Relative standard uncertainty of volumetric flasks which range from 2 mL to 100 mL were 0.398%?0.515%. Transferring 0.500?1.000 mL acetonitrile, relative standard uncertainty of pipettes were 0.587%?1.010%, which were higher than pipetting guns results 0.580%?0.595%, mainly causing by the larger relative standard uncertainty of repeatability. Transferring 0.100?0.500 mL acetonitrile, relative standard uncertainty of pipetting guns were 0.595%?0.917%. Transferring 20?100 μL acetonitrile, relative standard uncertainty of pipetting guns were 0.917%?1.755%. The results of relative standard uncertainty of measuring instruments caused by three plans for standard work curve preparation were 1.768%, 2.204% and 2.328%. Conclution Pipettes have higher operation requirements for experimenters, pipetting guns are easier to operate. Measurement repeatability experiment makes calibrating the measuring instruments periodically come true. When transferring different volumes of liquid, the pipettes and pipetting guns have different priority. Smaller volumetric flasks are preferred to metered volume, pipettes and volumetric flasks are preferred to prepare standard reserve solution and standard intermediate solution; pipetting guns can be used to prepare standard work curve solution.